PITTSBURGH, Jan. 6, 2015 – People with type 1 diabetes who intensively control their blood glucose soon after diagnosis are likely to live longer than those who do not, a recent report led by a University of Pittsburgh Graduate School of Public Health investigator revealed.
Data from a long-running trial and follow-up observational study funded by the National Institutes of Health (NIH), with participants from 27 academic medical centers in the U.S. and Canada, showed a 33 percent reduction in deaths over the past several decades among participants who had early, good control of their blood glucose. The findings are detailed in the current issue of the Journal of the American Medical Association (JAMA).
“We can now confidently tell doctors and patients that good, early control of blood glucose greatly reduces any risk for early mortality in people with type 1 diabetes, usually diagnosed in children and young adults,” said lead author Trevor Orchard, M.D., professor of epidemiology at Pitt Public Health. “These results also remove any lingering concern that intensive therapy may lead to increased mortality.”
The Diabetes Control and Complications Trial (DCCT) and the subsequent Epidemiology of Diabetes Control and Complications (EDIC) observational study have significantly changed treatment protocols for type 1 diabetes and improved the outlook for people with the condition over the past several decades, explained Griffin P. Rodgers, M.D., director of NIH’s National Institute of Diabetes and Digestive Kidney Diseases (NIDDK).
“Thanks to the findings over the years from the landmark DCCT/EDIC study, millions of people with diabetes may prevent or delay debilitating and often fatal complications from the disease,” said Dr. Rodgers. “NIH’s mission is to help improve lives through biomedical research. These kinds of results provide hard evidence that what we do helps people live longer, healthier lives.”
Type 1 diabetes happens when the body does not produce insulin, a hormone that is needed to convert sugar into energy. By regularly monitoring their blood glucose levels and adjusting doses of insulin accordingly, patients can work to keep their blood glucose in a normal range.
Beginning in 1983, the DCCT enrolled 1,441 volunteers between ages 13 and 39 with recent-onset type 1 diabetes. Half were randomly assigned to intensive efforts to keep blood glucose – also known as blood sugar – as close to normal levels as possible. The other half were assigned to the conventional treatment at the time, which simply sought to keep blood glucose levels from getting so high or low that patients would show symptoms, such as blurred vision or shortness of breath.
The trial ended in 1993 when the intensive group was found to have less eye, nerve and kidney disease. All participants were then taught the intensive blood glucose control techniques and early, good control of blood glucose was recommended for all people with type 1 diabetes. The EDIC study was then launched to continue tracking the health of all the participants.
Since 1983, 107 trial participants have died, with 64 in the group that originally received standard treatment, compared with 43 in the intensive treatment group.
The most common causes of death were cardiovascular disease at 22 percent, cancer at 20 percent and acute diabetes complications at 18 percent, all of which were more common in the group that originally received conventional treatment. Accidents or suicide were the fourth most common cause of death at 17 percent, with nominally more deaths in the people assigned to the early intensive treatment.
Higher average glucose levels and increased protein in the urine – a marker of diabetic kidney disease – were the major risk factors for death.
“These results build on earlier studies that suggested that increased protein in the urine largely accounts for shorter lifespans for people with type 1 diabetes,” said Dr. Orchard. “Our findings further emphasize the importance of good, early glucose control, as this reduces the risk for increased protein in the urine in general, as well as for diabetic kidney disease itself.”
While this study found an association between intensive blood glucose control and decreased mortality in people with type 1 diabetes, Dr. Orchard and his colleagues noted that the results cannot be extended to people with type 2 diabetes. Previous, unrelated studies have shown conflicting results for type 2 diabetes.
Additional authors on the JAMA publication are senior author John M. Lachin, Sc.D., of The George Washington University; co-authors Patricia Cleary, M.S., and Jye-Yu C. Backlund, M.P.H., also both of George Washington; David M. Nathan, M.D., Harvard Medical School; Bernard Zinman, University of Toronto; and David Brillon, M.D., Cornell University Medical Center.
This research was funded by NIH, with primary funding from the NIDDK, most recently under grant numbers U01 DK094176 and U01 DK094157. Additional NIH support for DCCT/EDIC was provided by the National Eye Institute, National Institute of Neurologic Disorders and Stroke, the General Clinical Research Centers Program and Clinical Translational Science Center Program.